The probability of meeting a random person who has the same birthday as you is 1/365, which is approximately 0.27%. What is the probability that it takes meeting more than 40 people before you meet someone who has the same birthday as you?

89.6%

Step-by-step explanation:

The probability a random person shares your birthday is 1/365, or 0.27%. That means the probability that they don't share your birthday is 364/365, or 99.73%.

So the probability that you meet 40 people who don't share your birthday is:

P = (364/365) ^40

P = 89.6%